The present contribution challenges the traditional etymology of the well-known ethnonym kagwahiva, which goes back to the first decades of the 20th century. It is shown that the hypothesized etymological association with the reflexes of the Proto-Tupi-Guarani *kap/*kaβ- ‘wasp’ is formally untenable. An alternative proposal is presented, supported by argumentation at phonological, morphological, semantic and syntactic levels, and based on the identification of clear, yet so far, unacknowledged cognates in Old Tupi, Old Guarani and other languages within the family. A PTG etymon *-kawaip/*kawaiβ- ‘to be aggressive, prone to violence’ is tentatively proposed, and further etymologization is advanced on the grounds of formal and semantic associations to *-kaʔu ‘to drink (alcoholic beverage)’.
